Introduction to chemical engineering

This week’s session will be fully dedicated to exercises aimed at strengthening your understanding of material balance fundamentals.

We will start with problems involving single-unit systems to build confidence with the basics. Once everyone is comfortable, we will progress to more challenging exercises involving multi-unit systems.

To support your work:

• Raw answers are already provided so you can check your progress as you go.

• Detailed solutions will be released after the class.

In addition, we have made available two short guides:

• Guide to Single-Unit Process Material Balance Calculations

• Guide to Degree-of-Freedom (DOF) Analysis

These are not part of the in-class session, but we encourage you to read them carefully, as they clarify the procedures you will need for your problem solving.

Finally, you will also find a BONUS midterm question from a previous year. This exercise is for extra training and to give you a sense of what to expect later in the semester. It will not be covered or discussed during this session, but you are welcome to attempt it on your own.

After studying this session you will be able to:

Dear students, 

Please note that there will be no lecture this week. Instead, we will hold a review session on material balances.

The session will be structured as follows:

• A short reminder of the methodology required to perform material balances on the different types of systems we have covered in class.

• Followed by a series of exercises to practice and strengthen your understanding.

This is a great opportunity to clarify any difficulties and reinforce your problem-solving skills before we move on to the next topics.

See you in class!

1. Validity of the reactions stoichiometry
2. There was a typo in the initial sheet, we have now uploaded the correct version, which is: "Assume that oxygen is twice the stoichiometric amount of oxygen needed for complete conversion of the CH3OH."

This week marks our last session on material balances, both non-reactive and reactive. By the end of it, you’ll have wrapped up the first part of the course and will be ready to dive into energy balances next!

This week, we’ll begin exploring one of the core topics in chemical engineering: energy balances. After focusing on material balances in previous weeks, we’ll now see how energy conservation principles apply to chemical processes and unit operations.

We will cover:

• The concept of energy balance and its analogy with mass balance

• The different forms of energy (internal, kinetic, potential, flow)

• How to formulate steady-state energy balance equations for simple systems

• Examples illustrating energy transfer in open and closed systems

Make sure to review your notes on system boundaries and process flow diagrams, as they will help you visualize where and how energy enters and leaves a system.

Looking forward to seeing you in class and working through the first energy balance examples together!

This week, we’ll extend our understanding of energy balances to reactive systems: processes in which chemical reactions occur and transform reactants into products. This is a key step in connecting thermodynamics with chemical process analysis.

We will cover:

• Introduction to the Enthalpy of Reaction: what it represents and how it relates to the energy released or absorbed during a reaction.

• Heat of Reaction Method: how to use reaction enthalpies directly in energy balance equations.

• Heat of Formation Method: an alternative approach using standard heats of formation of compounds.

• General Procedure for Energy Balances on Reactive Systems: a step-by-step method to formulate and solve these balances consistently.

By the end of this lecture, you should be able to analyze and solve energy balances involving chemical reactions, distinguishing between physical and chemical contributions to energy changes.

Make sure to review your notes on enthalpy, reference states, and previous energy balance formulations, as these concepts are essential for understanding how reactions modify the overall energy picture.

Looking forward to diving into reactive systems together!

Dear Students,

The Midterm Exam for ChE-201: Introduction to Chemical Engineering will take place on Friday, November 14, 2025, from 14:15 to 17:15 in Room CO 1.

We have also shared the seating plan and seat numbers in two separate files.
Please make sure to check your seat number before coming to the exam and sit in your assigned place.

Important reminders:

• Arrive at least 10 minutes early to locate your seat and settle in.

• Bring your student ID, calculator, and writing materials.

• Remember to bring all necessary materials (⚠️ do not forget your physical properties tables ⚠️) and any other allowed supplies.

• No electronic devices (phones, tablets, smartwatches, etc.) are allowed during the exam.

Exam content:

• Mass Balances: All types will be included, so please ensure you review each one.

• Energy Balance: This part will focus exclusively on Non-Reactive Systems.

Good luck with your preparation.

The Teaching Team

Dear students,

In today’s session, we will begin by reviewing the problems from last week’s midterm.

We will go through the correction of all three problems step by step, clarifying the key concepts and common pitfalls.

After the midterm review, we will continue with a classical exercise session, covering the two problems assigned for this week.

Looking forward to seeing you there!

Dear students,

Due to health reasons, Prof. Hatzimanikatis will not be able to give today’s lecture.

As a result, the final lecture of the course will take place next week, on Friday 5 December 2025. In this session, we will cover the remaining concepts of the class, namely heat of combustion and heat of solution.

For today’s session, you will have the opportunity to consult your midterm exam sheets, and we will also share with you final-exam-level problems so that you can begin preparing for the final assessment.

Thank you for your understanding.

Best regards,
The TA Team

Dear students,

In this week’s lecture, we will cover the following topics:

• Quick review on heat of reaction vs heat of formation methods

• Using Hess’s Law to compute the heat of reaction

• Heat of combustion

• Energy balances on mixing processes

• Distinction between ideal and real solutions

• Heat of solution

We look forward to seeing you in class.

Best,
The TA Team

Dear students,

This week’s session will be our last in-person class of the semester. We will use it for a final revision of the key concepts covered in the course. In particular, we will review the differences between the heat of reaction and the heat of formation methods. We will clarify how their reference states differ and why this matters. Heats of formation involve elements in their reference states, while heats of reaction are defined for molecular compounds. These distinctions play an important role in energy-balance calculations.

After the short revision, you will be free to continue working on the final exam revision problem sheet (Problem Sheet 9 – Week 11). We will also provide a selection of previous years’ final exams, so that you can practice and prepare effectively during the upcoming weeks.

Looking forward to seeing you all for this last session, and best of luck with your revision!

Dear students,

To help us better organize the course materials and reduce unnecessary paper printing, we kindly ask you to complete the Language Preference Questionnaire available below.

Through this questionnaire, you can indicate whether you prefer to receive printed materials in:

• English

• French

• Both languages

Your response will allow us to print only what is needed and avoid waste, while still ensuring that everyone receives materials in their preferred language.

Thank you for taking a moment to fill it out and for contributing to a more sustainable organization of the course.

Best regards,
The TA Team

Dear Students,

The final exam for this course is scheduled for Monday, 12th January 2026, from 15:15 to 18:15 in BCH 2201.

Please refer to the files linked below to find your assigned number and seat.

We wish you the very best of luck in your preparation and the exam.

Best regards,
The Teaching Assistants